A conventional liquid crystal display uses a pixel circuit to write and maintain data signals, and modulates the grayscale by the rotation of liquid crystal molecules. A modern liquid crystal display usually requires a high resolution and a high image quality, and the driving frequency for the liquid crystal display has been enhanced from initial 60 Hz to 120 hertz (Hz) and even to more than 240 Hz. In accordance with the driving frequency, the liquid crystal material used in the liquid crystal display needs to have a corresponding response speed. Therefore, such a liquid crystal material having a high response speed has been becoming a point to the liquid crystal display.
However, because of the material's property, the permittivity of such a liquid crystal material having a high response speed is affected by an operation frequency. For example, when the operation frequency is higher than a specific frequency, the permittivity will greatly decrease, resulting in the decreasing of equivalent capacitance value of the liquid crystal. Therefore, the voltage difference between the two ends of the liquid crystal cannot properly be modulated in response to the data signal. Also, the enhancement of the driving frequency causes the greater capacitance frequency effect of the liquid crystal material.